Bus bar circuit board structure

ABSTRACT

A new bus bar circuit board structure is provided. The structure comprises insulation substrates and a plurality of bus bars arranged on the insulation substrates parallelly with each other. The respective substrates have an edge portion and each bus bar has a portion bend erected from the respective substrate along the edge portion thereof to form frame-shaped gate portions, each frame-shaped gate portion being within another frame-shaped gate portion and separated therefrom by way of a gap when developed in plan view.

BACKGROUND OF THE INVENTION

This invention relates to an improvement in a bus bar circuit boardwhich constitutes an internal circuit in a junction box in which anumber of branch connections in an electric circuit for an automobileare made in a clustered manner.

Heretofore, prior art disclosed as a bus bar circuit board of this typein Japanese Utility Model Laid-Open No. 63828/1983 wherein a bus bar 3which used to have a bulging portion intended to avoid interference witha terminal 2 rising below an insulation substrate 1 or a developed state2' of a terminal 2 as shown in FIGS. 8A and 8B was proposed to be benderected like a gate-like rising bus bar 3a such that the substrate spaceis minimized as shown in FIG. 9.

However, there is a situation in which two rising bus bars 3a and 3bmust be arranged to run in parallel as shown in FIG. 10 in bus barcircuit design. In such a case, a partition wall 5 is protruded from themain cover 4 of the junction box A between the bus bars 3a and 3b toprovide insulation. Thus, there are problems that a distance l from theinside bus bar 3a to the outside bus bar 3b must be assured to allowinsertion of partition wall 5, the reduction in the size of insulatingsubstrate 1 does not become effective, and the laying density of the busbars is limited.

SUMMARY OF THE INVENTION

In order to solve the above mentioned problem, the invention provides abus bar circuit board structure comprising insulation substrate means;and a plurality of bus bars arranged on said insulation substrate meansparallelly with each other, said substrate means having an edge portion,said bus bars having a portion bend erected from said substrate meansalong said edge portion thereof to form frame-shaped gate portions, eachframe-shaped gate portion being within another frame-shaped gate portionand separated therefrom by way of a gap when developed in plan view.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an essential portion of an embodiment ofa bus bar circuit board structure according to the present invention;

FIG. 2 is a plan view of FIG. 1;

FIG. 3 is a sectional view taken along the line III--III of FIG. 2;

FIG. 4 is a developed view of erected bus bars in FIG. 1;

FIG. 5 is a front view of an essential portion of another embodiment ofa bus bar circuit board structure according to the invention;

FIG. 6 is a plan view of FIG. 5;

FIG. 7 is a sectional view taken along the line VII--VII of FIG. 6; and

FIGS. 8A, 8B, 9, 10 and 11 are explanatory views of prior art examples.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present invention will be described in detail withreference to the accompanying drawings.

In FIGS. 1 through 3, a bus bar circuit board structure B illustrates anexample in which two layers of insulation substrates 1 and bus bars 3are superposed to alternate in sandwich fashion. The reference 6 denotesan undercover of a junction box A or another bus bar circuit board.

Bus bar portions 3c and 3d of the upper and lower bus bars 3 are bent atthe edge portions of the upper and lower substrates 1 such that thelower bus bar is erected upward from below the lower substrate while theupper bus bars are erected from between the lower and upper substates,thus forming frame-shaped gate portions.

Further, the edge portions of the lower and upper substrates 1 arestaggered from each other such that the bus bar portion 3c takes aposition inward of the bus bar portion 3d by a distance l'.

Said bus bar portion 3c is smaller than the bus bar portion 3d to bewithin the space S defined by the frame of the bus bar portions 3d. Morespecifically, a suitable insulating gap E exists between the outer edge3c' of the bus bar portion 3c and the inner edge 3d' of the bus barportion 3d when the bus bar portions 3c and 3d are developed in planview as shown in FIG. 4.

FIGS. 5 through 7 show another embodiment of the invention, in which twoerected portions of the bus bar portions 3c and 3d are substantiallysuperposed; that is, the edge portions of said first and secondsubstrates are aligned with each other. In this case, a distance l"between the bus bars 3c and 3d becomes so near to zero that more spaceeconomy is accomplished than with the FIG. 2 embodiment.

According to the present invention, the bus bars will not contact witheach other even in the event of the bus bar portion 3d being tilted downto the other bus bar 3c as shown in FIG. 3, thus eliminating the needfor an insulation partition wall 5 as seen in the prior art of FIG. 11.

Therefore, the size of the bus bar circuit board can be reduced, thelaying density of the bus bars can be improved, and the internalstructure of the main cover 4 can be simplified.

Since the distance between the gate-shaped bus bars of the bus barcircuit board of the invention can be reduced as described above, thesize of the bus bar circuit board can be reduced, and the laying densityof the bus bars can be enhanced.

What is claimed is:
 1. A bus bar circuit board structurecomprisinginsulation substrate means; and a plurality of bus barsarranged on said insulation substrate means parallelly with each other,said substrate means having an edge portion, said bus bars having aportion bend erected from said substrate means along said edge portionthereof to form frame-shaped gate portions, each frame-shaped gateportion being within another frame-shaped gate portion and separatedtherefrom by way of a gap when developed in plan view.
 2. A bus barcircuit board structure according to claim 1, wherein said substratemeans includes a plurality of substrates piled on top of the others,said plurality of bus bars and said plurality of substrates alternatingin sandwich fashion.
 3. A bus bar circuit board structure according toclaim 2, wherein said plurality of substrates includes a first substrateand a second substrate while said plurality of bus bars includes a firstbus bar and a second bus bar, the edge portions of said first and secondsubstrates being staggered from each other such that said first bus baris bend erected from below the first substrate, and said second bus baris bend erected from between the first and second substrates.
 4. A busbar circuit board structure according to claim 2, wherein said pluralityof substrates includes a first substrate and a second substrate whilesaid plurality of bus bars includes a first bus bar and a second busbar, the edge portions of said first and second substrates being alignedwith each other such that said first bus bar is bend erected from belowthe first substrate, and said second bus bar is bend erected frombetween the first and second substrates.